Introduction to Proton Therapy

What is Proton therapy and why should you care?

Conventional Radiation therapy techniques use X-rays (‘photons’) to treat cancer by focussing X-rays on cancer regions. Proton therapy is a technique to treat cancer by the use of ‘protons’. The usage of protons to treat cancer may be advantages in various ways.

Radiation therapy for cancer treatment causes unnecessary exposure to healthy cells also, posing health risks on the patient. We can use Proton therapy for the following reasons.

We may want to expose children and pregnant women to lower amount of radiation.

Avoid “secondary cancers” that are caused by injury to DNA of nearby cells by radiation, used for treating the main or primary cancer. (Rare possibility but still possible)

How does Proton Therapy work?

A proton is a sub-atomic particle that is present in nucleus of each atom. In this therapy, protons are accelerated and focused on to region of cancer. It is focused so much that when it reaches the patient, it is only 2-5 mm in diameter. The proton beam characteristic of Bragg’s peak, allows us to engineer it in such a way that energy deposited on the cancer cell alone is very high. This reduces energy deposition (radiation dose) on other healthy cells which are present on the way. The same modification cannot be done for X-rays as they deliver dose to all cells they meet.

Current & Future trends:

Proton therapy is clearly superior for treating many types of cancers if not for the expenses involved. Proton therapy technology is much more compact than it was before but even this compact technology needs at-least few hundred square meters of hospital room. Most hospitals do not have the capital or building space to have proton therapy. The main aim of current proton therapy systems are to reduce space and bring more compact systems, sharpen proton beams even more and make it more accessible to public.

Fitting the whole proton therapy equipment in one room might allow some hospitals to replace existing technology with proton therapy equipment. As proton therapy becomes more and more established, the costs are definitely expected to reduce.